Off-site Transfers. An off-site transfer is a transfer of toxic chemicals in wastes to a facility that
is geographically or physically separate from the facility reporting under TRI. Chemicals
reported to TRI as transferred are sent to off-site facilities for the purposes of recycling, energy
recovery, treatment, or disposal. The quantities reported represent a movement of the chemical
away from the reporting facility. Except for off-site transfers for disposal, these quantities do not
necessarily represent entry of the chemical into the environment. The right side of Figure 1-1
illustrates transfer types reportable to TRI.

Transfers to Publicly Owned Treatment Works (POTWs). A POTW is a wastewater treatment
facility that is owned by a state or municipality. Wastewaters from facilities reporting under TRI
are transferred through pipes or sewers to a POTW. Treatment or removal of a chemical from the
wastewater depends upon the nature of the chemical, as well as the treatment methods present at
the POTW. In general, chemicals that are easily utilized as nutrients by microorganisms, or have
a low solubility in water, are likely to be removed to some extent. Chemicals that are volatile and
have a low solubility in water may evaporate into the atmosphere. Not all TRI chemicals can be
treated or removed by a POTW. Some chemicals, such as metals, may be removed, but are not
destroyed and may be disposed of in landfills or discharged to receiving waters.

Transfers Off-site for Recycling. Toxic chemicals in wastes that are sent off-site for the purposes
of recycling are generally recovered or regenerated by a variety of recycling methods, including
solvent recovery, metals recovery, and acid regeneration. The choice of the recycling method
depends on the toxic chemical being sent for recycling. Once they have been recycled, these
chemicals may be returned to the originating facility for further processing or made available for
use in commerce.

Transfers Off-site for Energy Recovery. Toxic chemicals in wastes sent off-site for purposes of
energy recovery are combusted off-site in industrial furnaces (including kilns) or boilers that
generate heat or energy for use at that location. Treatment of a chemical by incineration is not
considered to be energy recovery.

Transfers Off-site for Treatment. Toxic chemicals in wastes that are transferred off-site may be
treated through a variety of methods, including biological treatment, neutralization, incineration,
and physical separation. These methods typically result in varying degrees of destruction of the
toxic chemical. In some cases (such as stabilization or solidification), the chemical is not
destroyed but is prepared for further waste management, such as contained disposal.

Transfers Off-site for Disposal. Toxic chemicals in wastes that are transferred to a facility for
disposal generally are either released to land (see Box 1-1 above) at an off-site facility or are
injected underground.

Other Off-site Transfers. In this report, toxic chemicals in wastes that were reported as
transferred off-site but for which the off-site activity (i.e., treatment, disposal, energy recovery,
or recycling) was not specified or was not an accepted code have been classified as "other off-site
transfers."